Options on the Appearance page allow you to manage the look and feel of your end users' Home page.
Configure display options
Click Save when done.
Manage Sign-In background image
Images must be a .jpg, .png, or .gif, and less than 2MB in size.
Change the color scheme of your org
Under Application Theme, click a thumbnail to apply a different color scheme to your end user's My Applications home page. End users see the new theme when they sign in or refresh the page.